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RC1 82  .C36  The  mode  of  infectio 


RECAP 


FisKE  Fund  Prize  Dissertation.      No.  LII 


The  Mode  of  Infection 


AND 


Duration  of  the  Infectious  Period 


IN 


Scarlet  Fever. 


NIOXTO  : 

Dextrae  se  nostra  Scientia 
Implicuit,  sequiturque  Verum  non  passibus  acquis. 


CHARLES   V.   CHAPIN,   M.  D., 
Providence,  R.  I. 


CoHese  of  l^^psikimsi  anti  burgeons: 
itibrarp 


Digitized  by  the  Internet  Archive 

in  2010  with  funding  from 

Open  Knowledge  Commons 


http://www.archive.org/details/modeofinfectiondOOchap 


FisKE  Fund  Prize  Dissertation.      No.  LII. 


The  Mode  of  Infection 


AND 


Duration  of  the  Infectious  Period 


Scarlet  Fever. 


NIOTTO  : 

Dextrae  se  nostra  Scientia 
Implicuit,  sequiturque  Verum  non  passibus  acquis. 


BY 

CHARLES    V.    CHAPIN,   M.  D., 
Providence,  R.  I. 


PROVIDENCE: 
Snow  &  Fakhnam  Company,  Printers. 
1909. 


-RC!^^ 


THE  Trustees  of  the  Fiske  Fund,  at  the  annual  meeting  of  the 
Ehode  Island  Medical  Society,  held  at  Providence,  June  1,  1909, 
announced  that  they  had  awarded  a  premium  of  two  hundred  ($200) 
to  an  essay  on  "  The  Mode  of  Infection  and  Duration  of  the  In- 
fectious Period  in  Scarlet  Fever,"  bearing  the  motto  : 

"  Dextrae  se  nostra  Scientia 
Implicuit,  sequiturque  Verum  non  passitous  acquis." 

The    author   was    found    to   be    CHAKLES    V.    CHAPIN,    M.  D., 
of  Providence,  R.  I. 

DR.    FRANK   B.   FULLER,    Providence, 

DR.   EUGENE   KINGMAN, 

DR.   A.   A.   MANN,    Central  Falls, 

Trustees. 

HALSEY  DeWOLF,  M.  D.,  Providence, 

Secretary  of  the  Trustees. 


The  Mode  of  Infection  and  Duration  of  the 
Infectious  Period  in  Scarlet  Fever. 


It  is  much  to  be  regretted  that  the  specific  organism 
which  is  doubtless  the  cause  of  scarlet  fever  has  not 
as  yet  been  identified.  Various  observers  have  from 
time  to  time,  described  cocci,  or  bacilli,  which  they 
believed,  or  suspected  to  be,  the  cause  of  the  disease. 
Klein  isolated  a  diplococcus  which  for  a  while  was 
thought  by  many  to  be  the  specific  germ,  but  his 
observations  have  not  stood  the  test  of  time,  and 
neither  have  those  of  Class,  who  later  also  reported  a 
diplococcus  as  the  vera  causa.  More  recently  Mallory 
(1)  described  certain  bodies  in  the  skin  of  scarlet  fever 
patients  which  he  believed  to  be  protozoa,  and  which 
he  suspected  might  stand  in  causative  relation  to  the 
disease,  and  within  a  few  months  Gamaleia  (2)  has  also 
reported  finding  protozoan  forms  constantly  present. 
The  findings  of  these  last  two  observers  have  not  as 
yet  been  verified.  At  present  therefore  we  can  only 
employ  clinical  or  epidemiological  methods,  in  the  in- 
vestigation of  scarlet  fever,  and  such  methods  are 
difficult,  and  by  themselves  are  unlikely  to  yield 
decisive  results. 


6  THE  MODE  OE  INFECTION  AND  DURATION  OF 

Before  proceeding  to  the  discussion  of  the  subject, 
it  is  perhaps  well  to  call  attention  to  the  analogy  which 
has  been  supposed  to  exist  between  scarlet  fever  and 
smallpox.  There  is  a  good  deal  of  desquamation,  as 
well  as  shedding  of  the  crusts,  in  smallpox,  and  these 
crusts,  and  presumably  the  epidermis  also,  are  infec- 
tious. The  desquamation  in  scarlet  fever  has  been 
believed  to  be  similar  in  nature  to  that  of  smallpox, 
due  to  the  active  working  of  the  specific  poison  in  the 
skin,  and  therefore  also  infectious. 

A  more  careful  study  of  scarlet  fever  has  led  many 
to  see  that  this  resemblance  is  superficial  merely,  and 
that  scarlet  fever  seems  to  be  much  more  like  diphtheria 
than  any  other  disease.  The  age  incidence  of  the  two 
diseases  is  about  the  same,  as  is  also  the  degree  of 
infectivity.  The  period  of  incubation  is  nearly  the 
same.  A  long  latent  period  may  often  be  noted  in 
each.  Both  diseases  begin  with  sore  throat,  and  the 
throat  symptoms  are  usually  the  most  prominent 
symptoms,  and  are  so  nearly  alike  in  the  two  diseases 
that  except  for  the  rash  in  the  one  case,  and  the  find- 
ing of  diphtheria  bacilli  in  the  other,  it  is  difficult  in 
most  cases  to  make  a  diagnosis.  In  fact  many  cases  of 
scarlet  fever  are  before  the  e^ppearance  of  the  rash, 
considered  to  be  diphtheria.  In  both  diseases  albumi- 
nuria and  middle  ear  inflamation  are  common.  Both 
diseases  are  infectious  at  the  very  beginning,  and  the 
infectivity  gradually  disappears  in  a  few  weeks,  b;it  in 


THE    INFECTIOUS    PERIOD    IN    SCARLET    FEVEK.  7 

some  instances  may  be  retained  for  months,  and  often 
this  infectivity  seems  to  be  connected  with  a  chronic 
rhinitis.  Scarlet  fever  seems  to  be  as  much  a  local 
disease  of  the  throat  as  is  diphtheria.  The  eruption  in 
scarlet  fever  appears  much  more  likely  to  be  the 
result  of  a  toxemia,  than  to  an  actual  invasion  of  the 
skin  by  the  parasite,  as  is  the  case  in  smallpox. 

It  will  be  more  convenient  to  consider  the  duration 
of  infectivity  first,  and  modes  of  infection  afterwards, 
and  as  a  preliminary  step  we  may  inquire  as  to  the 
duration  of  incubation,  for  without  some  knowledge  of 
this,  it  is  difficult  to  determine  what  period  of  the 
disease  is  infectious. 

The  word  incubation  as  here  used,  merely  means  the 
time  which  elapses  between  the  implantation  of  the 
infectious  material  and  the  development  of  the  initial 
symptoms.  It  is  true,  incubation  carries  with  it  the 
idea  that  the  virus  of  the  disease  must  of  necessity 
have  a  more  or  less  definite  interval  in  which  to  multi- 
ply and  perhaps  pass  through  a  certain  portion  of  a 
more  or  less  complicated  life  cycle.  But  in  a  number 
of  infectious  diseases,  such  as  diphtheria,  it  is  known 
with  a  fair  degree  of  certainty  that  this  is  not  so.  In 
some  cases  as  soon  as  diphtheria  bacilli  are  planted  on 
a  mucous  surface  they  begin  to  proliferate  and  produce 
toxins,  and  probably  if  our  vision  were  acute  enough 
could  be  seen  to  cause  tissue  changes  within  a  remark- 
ably short  time.     Certainly  quite  marked  pathological 


8  THE  MODE  OF  INFECTION  AND  DURATION  OF 

conditions  are  sometimes  noticeable  in  a  few  hours. 
This  has  particularly  been  the  case  in  those  laboratory 
infections  where  the  moment  of  implantation  was 
known,  and  where  the  symptoms  were  carefully 
watched. 

According  to  most  observers  the  incubation  of  scarlet 
fever  is  usually  short,  in  most  instances  a  few  days  only. 
A  committee  of  the  Boston  Society  of  Medical  Improve- 
ment, appointed  to  consider  the  subject,  reported  (o) 
that  the  period  of  incubation  in  scarlet  fever  is  as  a  rule 
two  or  three  days,  but  may  be  extended  to  eight  days, 
and  possibly  twenty  (McCollom).  Reference  is  made 
by  the  above  committee  to  Murchison  (4)  who  collected 
reports  of  75  cases  in  which  the  period  of  incubation 
in  73  could  not  have  been  over  5  days,  in  54  it  could 
not  have  been  over  4  days,  in  20  not  over  3  days,  in 
15  not  over  2  days,  and  in  three  instances  it  could  not 
have  exceeded  24  hours.  The  committee  quote  from 
a  dozen  or  more  writers  whose  observations  and  opinions 
are  in  entire  accord  with  Murchison's.  Thus  Reimer 
found  that  in  two  thirds  of  3,624  cases  the  disease 
developed  within  the  first  three  days  after  exposure. 

The  writer's  experience  has  led  him  to  concur  in  the 
conclusions  as  stated  above,  that  is,  that  the  period  of 
incubation  is  usually  only  a  few  days,  and  that  it  may 
be  only  a  few  hours.  This  conclusion  is  based  upon 
First;  the  time  when  secondary  cases  develop  in  the 
family.     Second ;  the  time  when  other  families  in  the 


THE    INFECTIOUS    PERIOD   IN    SCARLET    FEVER.  9 

same  house  develop  the  disease.  Third;  the  time  when 
cases  develop  in  the  family  after  return  from  the  hos- 
pital. Fourth ;  the  time  when  well  children  sent  away 
from  home  sicken  with  the  disease  while  away  or  after 
their  return,  and  Fifth ;  a  few  special  instances.  Tables 
illustrating  the  first  two  points  are  given  on  pages  12 
and  13. 

Hospital  return  cases  from  my  own  experience  are 
not  very  numerous,  but  the  facts  correspond  with  the 
English  data  given  by  Cameron  and  Turner.  In  the 
latter's  experience  441  of  1,129  ''return  cases"  of 
scarlet  fever  occurred  in  the  first  week.  Of  my  own  41 
observed  cases  23  were  in  the  first  week  after  return. 
Of  52  well  persons  who  were  removed  from  scarlet 
fever  houses  under  my  observation,  and  who  were 
afterwards  taken  sick,  29  developed  the  disease  during 
the  first  week. 

While  it  is  possible  that  in  the  majority  of  cases  of 
scarlet  fever  the  period  of  incubation  is  only  a  few 
days,  it  may  be  prolonged  perhaps  for  weeks.  We 
know  that  the  period  of  incubation  is  usually  short  in 
diphtheria,  but  that  sometimes  a  person  may  harbor 
diphtheria  bacilli  in  throat  or  nose  for  weeks,  and  yet 
remain  perfectly  well,  and  then  finally  the  disease  will 
develop.  It  is  probable  that  precisely  the  same  thing 
happens  in  scarlet  fever.  Welch  and  Schamberg  (5) 
quote  Hagenbach-Burchhardt  and  Holt  as  reporting 
many  cases  of  prolonged  incubation  some  extending  as 


10  THE  MODE  OF  INFECTION  AND  DURATION  OF 

long  as  21  days.  It  is  probable  that  from  a  pathological 
standpoint,  incubation  in  scarlet  fever  has  little  meaning. 
The  fact  that  cases  returning  from  a  hospital  may  be 
slow  in  infecting  the  family,  or  that  well  members  of 
the  family  returning  home  after  the  termination  of 
isolation,  may  not  quickly  develop  the  disease,  probably 
means  that  in  these  instances  the  virus  of  the  disease 
is  small  in  amount,  or  is  not  thrown  off  continuously 
from  the  infecting  case.  Thus  an  intermittently  dis- 
charging ear  would  readily  explain  cases  of  delayed 
infection  or  what  would  apparently  be  prolonged 
incubation. 

DURATION    OF    THE    INFECTIOUS    PERIOD. 

There  is  much  evidence  to  show  that  scarlet  fever  is 
infectious  in  the  early  stages,  particularly  during  the 
height  of  the  throat  symptoms.  A  considerable  num- 
ber of  cases  are  on  record  where  a  person  exposed  to 
scarlet  fever  during  this  period  contracted  the  disease. 
Several  of  these  are  mentioned  on  pages  23  and  25  of 
this  essay.  This  evidence  from  individual  cases  is  also 
in  accord  with  much  statistical  evidence.  The  follow- 
ing tables  prepared  by  the  writer  show, 

First,  The  time  at  which  secondary  infections  occur 
in  the  family. 

Second,  The  time  at  which  other  families  in  the 
house  become  infected. 


THE   INFECTIOUS    PERIOD   IN    SCARLET    FEVER.  H 

These  tables  indicate  that  in  a  large  proportion  of 
the  families  the  infection  of  others  takes  place  during 
the  first  week  of  the  disease.  This  would  scarcely  be 
possible  unless  the  period  of  incubation  was  short  and 
the  disease  infectious  in  the  early  stages. 


12 


THE  MODE  OF  INFECTION  AND  DURATION  OF 


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THE   INFECTIOUS    PERIOD    IN    SCARLET    FEVER. 


13 


TABLE  n.    SCARLET  FEVER. 

Time  of  Infection  of  Other  Families  ia  House. 


After  Termination  of  Isolation. 

During  ] 

Period  of  Isola- 
FiRST  Sickness. 

TION  OF 

Dav  of  Initial  Sickness. 

Day  of  Release  from 
Isolation. 

.2 

■+-( 

.y 

4h 

<^ 

<H 

■w     . 

o 

t> 

0 

i 

0 

0 

11 

B6 

''-   CO 

1 

0 

a 

0 

1 

CIS 

la 

?? 

a)  03 

ia 

« 

a 

12; 

Q 

12; 

a 

z 

1 

9 

38 

1 

:  1 

38 

1 

1 

38 

2 

6 

39 

2 

39 

i" 

2 

1 

39 

3 

6 

40 

.... 

i  0 

40 

3 

40 

i 

4 

3 

41 

i  '^ 

41 

4 

i 

41 

5 

7 

42 

2 

!  5 

42 

5 

42 

6 

4 

43 

. . . . 

i  6 

43 

"'i' 

6 

.... 

43 

7 

2 

44 

i" 

7 

44 

7 

44 

8 

4 

45 

1 

8 

45 

8 

45 

9 

2 

46 

'! 

i  9 

46 

9 

1 

46 

10 

1 

47 

.... 

ilO 

47 

i' 

10 

3 

47 

11 

1 

48 

111 

48 

11 

48 

12 

3 

49 

112 

49 

"2" 

12 

49 

.... 

13 

4 

50 

[13 

50 

13 

50 

14 

2 

51 

!14 

51 

*  •  ■  > 

14 

51 

.... 

15 

52 

"i" 

|15 

52 

15 

52 

16 

53 

1 

;16 

53 

16 

63 

1 

17 

l' 

54 

1 

il7 

54 

17 

2' 

54 

18 

55 

•  •  ■  • 

il8 

55 

'  2 

18 

55 

.... 

19 

56 

.  .  .  ■ 

jl9 

56 

19 

56 

20 

1 

57 

!20 

'2' 

57 

"i' 

20 

57 

21 

58 

'21 

58 

21 

"i" 

58 

"i" 

22 

"i" 

59 

.... 

I22 

59 

i 

22 

59 

23 

.... 

60 

!23 

60 

1 

23 

.... 

60 

.... 

24 

Srcl   mo. 

2 

24 

3rd   mo. 

11 

24 

3rd.   mo. 

8 

25 

1 

4tli      " 

25 

4th     " 

6 

25 

4th     " 

2 

26 

1 

5th      '•■ 

126 

5th      '' 

26 

5th      " 

27 

6th      " 

27 

6th      " 

1' 

27 

.... 

6th     " 

2 

28 

'2' 

7th      " 

28 

7th      " 

3 

28 

7th      " 

3 

29 

1 

8th      " 

29 

8th      " 

1 

29 

1 

8th      " 

.... 

30 

2 

9th      " 

I30 

9th     " 

30 

1 

9th     " 

31 

.  .  .  • 

10th      " 

|31 

""i" 

10th      " 

31 

10th     " 

"i' 

32 

11th      ^'■ 

32 

11th     *' 

i' 

32 

"i' 

11th      '' 

.... 

33 

12  th      " 

133 

12th      •' 

.  .  .  • 

33 

12th      " 

34 

34 
35 

1 

13th      '' 

1 

34 

35 
36 

37 

35 

2" 

1 

36 

36 

37 

38 

.... 



37 

80  1 

38 

14  THE  MODE  OF  INFECTION  AND  DURATION  OF 

That  the  infectivity  is  at  its  height  during  the  early 
days  of  the  disease,  and  that  it  diminishes  quite  rapidly 
after  the  disappearance  of  the  throat  symptoms  and 
the  rash,  also  seems  to  be  indicated  by  the  data  just 
given.  This  however  is  contrary  to  the  popular 
notion,  for  most  of  the  laity,  and  many  physicians, 
consider  that  scarlet  fever  is  much  more  infectious  dur- 
ing desquamation  than  at  any  other  time.  As  will  be 
shown  when  discussing  the  infectiousness  of  the  ex- 
foliated epidermis  there  does  not  appear  to  be  any 
experimental  or  clinical  evidence  of  this.  Yet  it  must 
be  admitted  that  while  the  facts  of  rapidly  diminish- 
ing extension  of  the  disease  in  and  out  of  the  family, 
is  in  accord  with  the  view  that  the  infectivity  also 
rapidly  diminishes  after  the  disappearance  of  the  acute 
symptoms,  it  is  not  a  proof  of  it,  for  the  decreasing 
number  of  cases  in  the  family  may  be  due  to  the  using 
up  of  all  susceptible  material,  and  failure  to  extend 
beyond  the  family  may  be  due,  in  part,  as  seems  to 
the  writer  probable,  to  the  success  of  the  isolation 
which  is  enforced  as  soon  as  the  cases  are  recognized. 
But  surely  there  is  nothing  in  these  facts  to  indicate  a 
greater  degree  of  infectiousness  during  the  later  than 
during  the  earlier  stages  of  the  disease. 

The  following  facts  do  indicate  quite  clearly  the 
diminishing  infectivity  during  the  later  stages.  I 
have  records  of  the  removal  of  493  well  children  from 
families   where  there  was  scarlet   fever,  showing  the 


THE    INFECTIOUS    PERIOD    IN    SCARLET    FEVER.  15 

time  at  which  they  returned.  Unfortunately  I  made 
no  record  of  cases  that  returned  home  within  a  week, 
but  probably  these  would  have  shown  an  equal  or 
even  higher  incidence  of  the  disease. 

Number  of  Weeks  Away.      Over     Un-  Total 

12345677    kaown.    Children. 

Children  who  were  at- 
tacked on  return 75552000         0  24 

Children  who  were  not 
attacked  on  return..       20    29    86    87  126    74    18    21        8  469 

The  rapidly  diminishing  infectivity  of  the  disease  is 
plainly  shown  by  these  figures.  It  is  well  known  that 
the  specific  bacilli  not  rarely  disappear  from  cases  of 
diphtheria  within  a  week  or  ten  days  of  the  onset  of 
the  disease.  In  my  own  city  only  1.8  per  cent  of  the 
cases  retain  their  infection  for  ten  weeks  or  more.  The 
various  data  that  have  been  presented  concerning  scar- 
let fever  indicate  that  the  infectivity  of  this  disease 
also  disappears  in  much  the  same  way,  as  does  that  of 
diphtheria.  Barlow  (6)  and  Zilgien  (7)  have  recently 
considered  this  subject,  and  believe  that  in  view  of  all 
the  facts,  we  are  justified  in  assuming  that  in  a  large 
number  of  mild  cases  of  scarlet  fever,  the  infectivity 
disappears  by  the  end  of  the  third  week. 

Unfortunately  we  have  no  means  of  determining  in 
this  disease  as  we  have  in  diphtheria,  the  cases  in 
which  this  happens.     An  arbitrary  time  limit  has   to 


16  THE  MODE  OF  INFECTION  AND  DUEATION  OF 

be  fixed  for  the  minimum  period  of  isolation  in  scarlet 
fever.  In  the  majority  of  cities  this  is  fixed  at  six 
weeks,  and  in  some  English  cities  at  seven  or  eight 
weeks,  but  in  certain  American  cities  it  is  much  less. 
Thus  it  is,  or  was  for  many  years,  five  weeks  in  Eoches- 
ter,  four  weeks  in  Brookline,  Mass.,  Concord,  N.  H., 
Newton,  Mass.,  Kansas  City  and  Omaha,  and  three  weeks 
in  Buffalo,  Cambridge,  Grand  Rapids,  Holyoke,  Lowell, 
Minneapolis,  Newark,  New  York  City,  Syracuse  and 
Utica.  Scarlet  fever  is  even  more  prevalent  in  English 
cities  than  it  is  in  the  cities  of  the  United  States,  and 
a  study  of  the  disease  in  the  latter  country  does  not  in- 
dicate that  the  cities  which  maintain  a  longer  period 
of  isolation  have  an  appreciably  less  amount  of  disease 
than  do  those  with  a  shorter  period.  In  Providence 
the  period  of  isolation  was  shortened  from  five  to  four 
weeks  without  noticeable  change  in  the  prevalence  of 
the  disease.  It  is  indeed  true  that  nearly  always  the 
minimum  period  of  isolation  is  exceeded  if  desquama- 
tion continues,  but  as  will  be  seen,  it  is  probable  that 
the  exfoliated  epidermis  is  not  infectious.  It  is  fair  to 
infer  from  these  facts  that  the  infectivity  of  scarlet 
fever  in  its  later  stages  is  not  very  great. 

It  is  certain  however  that  a  small  number  of  cases 
remain  infectious  for  a  very  long  time,  just  as  some 
cases  of  diphtheria  may  remain  carriers  of  the  bacilli 
for  many  weeks  or  months,  and  it  seems  probable  that 
this  late  infectivity  in  scarlet  fever  is  somewhat  more 


THE   INFECTIOUS    PERIOD    IN    SCARLET    FEVER.  17 

prolonged  and  frequent  than  it  is  in  diphtheria.  This 
subject  may  best  be  studied  in  connection  with  cases 
which  carry  home  infection  from  the  isolation  hospital. 
The  English  data  are  much  the  most  valuable  for  this 
purpose  as  the  hospitalization  of  patients  is  carried 
further  there  than  in  other  countries,  and  the  subject 
has  been  more  carefully  studied.  Three  repoi'ts  have 
been  made  concerning  these  "return  outbreaks"  of 
scarlet  fever  and  diphtheria  in  the  London  hospitals, 
covering  the  years  1899  to  1904.  The  number  of 
scarlet  fever  cases  discharged  from  the  hospitals  during 
this  period  was  57,810,  and  the  number  of  "  infecting 
cases "  i.  e.  cases  which  carried  infection  home  from 
the  hospital  was  2,225,  or  3.8  per  cent.  It  has  been 
argued  that  a  good  many  of  the  apparent  instances  of 
"return  infection"  are  merely  coincidences,  but 
Turner  (8)  has  shown  that  this  can  be  true  of  only  a  very 
small  number.  Turner  has  presented  his  facts  in  the 
form  of  diagrams  which  are  well  worth  studying. 
These  diagrams  show  the  time  distribution  of  the  cases 
which  develop  after  the  return  of  the  infecting  case, 
and  it  appears  highly  improbable  that  more  than  a 
very  few  can  be  coincidences,  or  due  to  a  lingering  in- 
fection in  members  of  the  family  remaining  at  home, 
or  in  the  house  itself.  Such  a  large  series  of  cases 
gives  an  excellent  opportunity  for  studying  the  dura- 
tion and  mode  of  infection  in  this  disease. 


18 


THE  MODE  OF  INFECTION  AND  DURATION  OP 


The  following  table  taken  from  Cameron's  (9)  report 
shows  the  time  of  detention  in  certain  hospitals  of  all 
cases  of  scarlet  fever  treated  in  them,  and  also  the 
time  of  detention  of  the  infecting  cases,  that  is  of  the 
cases  which  carried  the  infection  to  their  homes. 


TABLE  m. 

(August,  J  90},  to  July,  1902,  indusivc.) 


-4 

-6 

-8 

-10 

-12 

-14 

-16 

to 

'c3 

g^ 

O 

g 

"Infecting 

Cases  ". . . 

3 

41 

209 

210 

112 

34 

24 

20 

653 

Percentage . 

.45 

6.27 

32.06 

32.15 

17.13 

5.20 

3.67 
6. 

3.06 
73 

"All  Cases" 

15 

88 

975 

5,070 

4,667 

2,258 

1,222 

12 

06 

15.501 

Percentage . 

.09 

.56 

6.28 

32.70 

30.10 

14.56 

7.88 

7. 

78 

This  table  shows  that  in  609  instances  the  infectivity 
was  prolonged  beyond  6  weeks,  in  190  instances 
beyond  10  weeks,  in  44  instances  beyond  14  weeks  and 
in  20  instances  beyond  16  weeks.  A  similar  prolonga- 
tion of  infection  is  also  shown  by  the  tabulation  of  the 
1,085  infectious  cases  in  Turner's  (10)  report  which  is 
shown  on  the  following  page: 


THE   INFECTIOUS    PERIOD    IN    SCARLET   FEVER. 


19 


TABLE  IV. 

Period  of  detention  of  infecting  cases  (primary  Scarlet  Fever  only). 


Detention  in  dats. 

1902. 

1903. 

1904. 

Total. 

14  to  20 

2 

3 

4 

18 

82 

96 

83 

68 

46 

35 

14 

11 

2 

10 

3 

1 

3 

3 

2 

21 

2 
11 

18 

57 

62 

48 

45 

30 

25 

16 

13 

7 

4 

5 

2 

2 

1 

1 

4 

13 

41 

58 

44 

26 

13 

11 

7 

14 

4 

3 

3 

4 

1 

6 

28 

19 

35 

49 

42 

180 

49 

216 

56 

175 

63 

139 

70 

89 

77 

71 

84 

37 

91 

38 

98 

13 

105 

17 

112 

11 

119 

7 

126 

5 

133 

5 

140 

147 

1 

1 

"'i' 

1 

154 

1 

161 

2 

1 

3 

168-175 

1 

486 

350 

249 

1,085 

Period    of    detention    uncertain,    two   or 
more  infecting  cases  having  Ibeen  dis- 
charged after  different  periods  of  deten- 

16 

20 

11 

47 

Totals 

502 

370 

260 

1,132 

The  longest  period  noted  by  Turner  was  over  24 
weeks.  Instances  of  prolonged  infectivity  in  scarlet 
fever  may  occasionally  be  found  in  medical  literature. 
A  number  are  reported  by  Newsholme  (11).  Other  are 
given  by  Cameron  (12)  in  one  of  which  the  infectivity 


20  THE  MODE  OF  INFECTION  AND  DURATION  OF 

lasted  over  16  weeks,  or  10  weeks  after  discharge  from 
the  hospital.  Zilgien  (7)  reports  an  instance  where  a 
girl  probably  remained  infectious  from  July  6  until  the 
following  March.  Simpson  (13)  gives  several  instances 
of  prolonged  infectivity,  one  of  them  extending  over 
240  days,  or  8  months.  Most  of  these  cases  of  long 
standing  infection  have  some  discharge  from  nose  or 
ear.  I  have  seen  a  case  of  scarlet  fever  which  was 
taken  sick  on  June  25,  and  was  discharged  from  the 
hospital  on  November  15,  apparently  giving  rise  to  two 
other  cases  within  a  few  days.  This  case  had  a  dis- 
charge from  the  ear.  Such  very  prolonged  infectivity 
is  apparently  not  very  common.  The  20  cases  reported 
by  Turner  as  lasting  over  16  weeks  were  only  3  per 
cent  of  653  infecting  cases  discharged  from  the  hospital, 
and  only  0.12  per  cent  of  the  whole  15,501,  cases 
discharged. 

It  will  also  be  seen  from  the  tables  that  the  patients 
who  remain  in  the  hospital  from  8  to  12  weeks  furnish 
the  largest  number  of  return  cases.  From  this  fact,  as 
well  as  from  other  considerations,  Simpson,  as  well  as 
various  other  writers,  have  argued  that  infectivity  is 
increased  by  prolonged  residence  in  a  hospital,  because 
the  patients  absorb  the  scarlet  fever  virus,  perhaps  in 
more  virulent  form,  from  other  patients  in  the  ward. 
Both  Cameron  and  Turner  hold  that  this  is  probably 
not  so.  One  reason  why  patients  detained  over  8 
weeks  are  more  likely  to  prove  infective,  is  because 


THE    IKFBCTIOUS    PERIOD   IN    SCARLET    FEVER.  21 

they  are  usually  retained  on  account  of  some  complica- 
tion, which  indicates  a  probably  great  virulence  of  the 
disease  poison.  Complicating  discharge  from  nose  and 
ear  directly  maintain  inf  ectivity.  The  figures  also  sho^ 
that  the  longer  these  complicated  cases  are  kept  in  the 
hospital,  so  that  opportunity  may  be  afforded  for  com- 
plete recovery,  the  fewer  are  the  resulting  return 
cases,  which  could  not  be  if  infectivity  were  caused  by 
long  residence  in  the  hospital.  That  the  duration  of 
infection  depends  on  the  type  of  the  disease,  virulence 
of  the  virus,  and  the  complications,  and  not  on  hos- 
pitalization is  also  urged  by  Newsholme.  The  height- 
ened virulence  of  the  infecting  cases,  is  shown  by  the 
fact,  as  set  forth  by  Cameron,  (14)  that  the  case  fatality 
of  the  return  cases  caused  by  them  is  5.8  as  compared 
with  3.6  of  all  cases. 

If  cases  are  treated  at  home  late  recurrence  of  the 
disease  is  noted  there  also.  Thus  in  Providence,  after 
disinfection,  there  is  a  recurrence  of  the  disease  in  the 
same  families  in  about  1.2  per  cent  of  the  families,  and 
in  other  families  in  the  house  in  2.4  per  cent  of  the 
families.  Disinfection  is  usually  done  at  the  fifth  or 
sixth  week.  So  also  when  well  children  are  sent  away 
from  home  they  will  sometimes  contract  the  disease  on 
their  return,  and  as  shown  on  page  15  the  danger 
decreases  rapidly.  Of  1,671  susceptible  persons  mostly 
children  so  removed  and  returned  after  the  termination 


22  THE  MODE  OF  INFECTION  AND  DURATION  OF 

of  isolation,  usually  about  the  fifth  or  sixth  week,  31 
or  1.2  per  cent  have  been  taken  sick  with  the  disease. 

The  tables  show  also,  particularly  those  of  Turner, 
that  the  cases  discharged  before  6  weeks  have  a  lower 
infectivity  than  those  discharged  later.  These  early 
cases  are  mild  and  uncomplicated,  and  apparently  lose 
their  infecting  power  before  the  others. 

Some  are  beginning  to  think  that  the  period  of 
isolation  for  scarlet  fever  has  been  unduly  prolonged, 
at  least  in  England,  and,  as  will  be  shown  later,  the 
average  period  of  detention  in  the  hospital,  has  in 
several  towns  been  materially  reduced  without  causing 
any  increase  in  the  number  of  return  cases.  Barlow 
(16)  thinks  that  many  mild  cases  are  infectious  but  a 
few  days.  Zilgien  (17)  agrees  with  Barlow  and  gives 
instances  where  isolation  during  the  sore  throat  only, 
proved  sufficient. 

From  a  consideration  of  the  facts  here  presented  it 
appears  that  cases  of  scarlet  fever  are  infectious  from  the 
very  beginning,  that  the  period  of  greatest  infectivity 
is  probably  during  the  presence  of  the  acute  symptoms, 
sore  throat,  fever  and  rash,  that  it  probably  diminishes 
rather  rapidly  after  the  disappearance  of  these  symp- 
toms, and  that  by  the  end  of  four  weeks  has  disap- 
peared from  all  but  a  small  percentage  of  the  cases. 
That  in  some  instances  infectivity  may  persist  for 
many  weeks  and  even  for  several  months. 


THE    INFECTIOUS    PERIOD    IN    SCARLET    FEVER.  23 

SOURCES     OF    THE    INFECTION    IN    THE    BODY. 

It  is  now  necessary  to  consider  the  source  of  the 
virus  in  the  human  body  in  order  that  we  may  the 
better  determine  the  conditions  under  which  individual 
patients  are  infective. 

The  Throat.  There  is  much  reason  for  thinking 
that  the  specific  poison  of  scarlet  fever  is  contained  in 
the  secretions  of  the  throat  in  the  early  stages  of  the 
disease,  and  perhaps  it  may  persist  there,  in  some  at 
least,  of  the  cases  of  long  continued  infection.  The 
pathological  process  is  most  acute  and  marked  in  the 
throat,  and  the  contagiousness  of  the  disease  is  great- 
est during  the  acute  stages  and  rapidly  diminishes  with 
the  abatement  of  the  throat  symptoms.  There  are 
also  a  few  direct  observations  which  are  in  accord  with 
this  view.  Jurgensen  (15)  says  that  Copland  reports  a 
case  infected  by  the  sputum  in  the  early  stages  of  the 
disease.  Stickler  (16)  inoculated  into  10  children  mucus 
taken  from  the  throat  of  a  patient  just  after  the  rash 
appeared.  Every  child  developed  within  from  12  to 
72  hours  a  fair  picture  of  scarlet  fever.  Griinbaum 
(17)  reports  a  single  instance  of  the  possible  infection 
of  an  ape  with  the  secretion  from  the  throat  of  a 
scarlet  fever  patient.  Cameron  (18)  shows  in  the 
accompanying  table  that  while  morbid  conditions  of 
the  throat,  such  as  enlarged  tonsils,  and  inflammation 
with  excessive  secretion,  were  reported  from  only  6.3 


24 


THE  MODE  OP  INFECTION  AND  DURATION  OF 


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THE   INFECTIOUS   PERIOD   IN   SCARLET   EEVEE.  25 

per  cent  of  the  total  scarlet  fever  cases  discharged  from 
the  hospital,  such  conditions  were  associated  with 
32.25  per  cent  of  the  infecting  cases.  Scarlet  fever 
sine  eruptione,  that  is  with  the  symptoms  confined  ex- 
clusively to  the  mucus  surfaces,  chiefly  the  throat,  are 
reported  by  all  writers  on  this  disease.  It  is  the  in- 
fectivity  of  these  cases  which  establishes  the  diagnosis, 
and  the  fact  that  they  are  infectious,  though  throat 
symptoms  only  are  apparent,  strengthens  the  conclu- 
sion that  the  throat  is  the  seat  of  infection.  Cameron 
(19)  reports  104  cases  of  possible  scarlet  fever  sore 
throats  many  of  which  proved  infectious.  A  milk 
outbreak  with  many  such  cases  is  described  by  News- 
holme  (20). 

In  the  JSfose.  In  diphtheria  the  specific  bacillus  is 
found  rather  more  often  in  the  nose  than  in  the  throat, 
so  we  would  expect  that  in  scarlet  fever,  the  nose  as 
well  as  the  throat,  might  be  infected.  Nasal  discharge 
may  be  observed  at  any  stage  of  the  disease,  but  it  is 
only  in  the  later  stages  that  its  infectivity  seems  to  be 
established.  The  middle  ear  trouble  which  is  so  fre- 
quent a  complication  of  scarlet  fever,  is  doubtless  due 
to  an  extension  of  the  pathological  process  from  the 
naso-pharynx,  A  similar  extension  takes  place  in 
diphtheria,  much  more  commonly  than  is  usually  stated. 
That  some  form  of  rhinitis,  usually  virulent,  is  fre- 
quently associated  with  prolonged  infectivity,  has  been 


Ii6  THE  MODE  OP  INFECTION  AND  DURATION  OP 

noted  by  a  number  of  English  observers  as  Newsholme, 
Pugh,  Niven,  Lauder,  Simpson,  Cameron  and  Turner, 
and  is  well  shown  by  Cameron's  table  shown  on  page 
24.  He  shows  that  of  the  infecting  cases  dis- 
charged from  the  hospital  52.31  per  cent  had  some 
form  of  rhinitis,  while  of  the  total  cases  only  3.56  per 
cent  had  this  complication. 

It  is  observed  that  nasal,  and  also  aural  discharge, 
in  convalescent  scarlet  fever  patients,  is  not  contin- 
uous, but  that  often  a  number  of  days  or  weeks  elapse 
in  which  there  is  no  discharge.  A  renewal  of  the  dis- 
charge from  the  nose  is  sometimes  accompanied  by  a 
recrudesence  of  infectivity,  shown  by  the  patient 
transmitting  the  disease  to  another.  Thus  Cameron 
(21)  reports  a  case  which  was  discharged  well  from  the 
hospital,  but  22  days  later  a  rhinitis  developed,  and 
another  case  in  the  family  was  taken  sick  in  5  days. 
Cameron  gives  a  score  or  more  of  such  cases. 

Besides  the  fact  that  a  persistent  sore  throat  and 
an  excessive  nasal  discharge  are  found  to  a  considerable 
excess  in  infecting  cases,  and  that  recrudesence  of 
these  symptoms  is  followed  by  the  development  of 
fresh  cases,  evidence  of  the  infective  nature  of  these 
discharges  is  found  in  the  decrease  in  the  number  of 
return  cases  where  special  care  has  been  taken  not  to 
send  home  patients  in  which  throat  and  nose  symp- 
toms are  present.  In  many  of  the  English  hospitals 
less  attention  is  being  paid  to  desquamation  and  more 


THE   INFECTIOUS    PERIOD   IN    SCARLET   FEVER.  27 

to  the  condition  of  the  nose  and  pharynx.  The  result 
is  that  in  London,  Birmingham,  Manchester,  South- 
ampton, Huddersfield,  and  other  places  the  number  of 
return  cases  is  diminishing,  and  at  the  same  time  the 
period  of  detention  in  the  hospital  has  been  materially 
shortened. 

The  Ear.  A  discharging  ear  in  a  convalescent 
scarlet  fever  patient  has  long  been  believed  to  be  in- 
fectious, and  is  still  considered  so  by  most  observers. 
Cameron  (22)  thinks  it  is  not  proved  that  otorrhea  is 
infectious,  and  he  suspects  that  it  is  not.  Of  123 
patients  with  otorrhea,  only  8  caused  the  infection  of 
others,  and  in  all  of  these  there  existed  a  concurrent 
rhinitis.  Nevertheless  he  shows,  p.  24,  that  while 
only  2.16  per  cent  of  all  discharged  scarlet  fever  cases 
have  otorrhea,  at  the  time  of  discharge,  8.33  per  cent 
of  the  infecting  cases  had  it.  Otorrhea  frequently 
occurs  in  diphtheria,  and  I  have  repeatedly  found  the 
diphtheria  bacillus  in  the  discharge,  as  have  others. 
We  should  expect  also  to  find  the  discharge  infectious 
in  scarlet  fever,  and  it  does  not  appear  on  present 
evidence  to  be  safe  to  consider  it  otherwise.  An 
otorrhea  may  last  a  very  long  time,  but  the  discharge 
is  often  very  slight,  and  in  many  instances  it  is  not 
necessary  to  isolate  the  patient  if  the  ear  is  properly 
cared  for,  and  perhaps  kept  plugged  with  cotton. 


28  THE  MODE  OF  INFECTION  AND  DURATION  OF 

The  Skin.  From  time  immemorial  the  desquamat- 
ing skin  of  scarlet  has  been  considered  not  merely  in- 
fectious, but  even  as  the  sole  vehicle  of  infection.  It 
is  not  surprising  that  this  view  should  have  arisen, 
for  the  desquamation  of  smallpox  was  demonstrated  by 
inoculation  to  be  infectious,  and  that  of  scarlet  fever 
was  by  analogy  assumed  to  be  so.  Desquamation  per- 
sists a  long  time,  as  does  the  infectivity,  and  the  two 
often  disappear  together.  Formerly  the  air  was  be- 
lieved to  be  the  chief  carrier  of  infection,  and  what 
could  be  more  readily  carried  by  the  air  than  the  light 
and  fine  epidermal  scales  ?  But  of  late  years  many 
have  begun  to  question  the  infectivity  of  the  ex- 
fohated  epidermis.  Among  these  may  be  mentioned 
Boobbyer  (23),  Richards  (24),  Gilbert  (25),  Millard  (26), 
Lauder  (27),  Cameron  (28),  Bond  (29),  Moore  (30), 
Turner  (31),  and  Lemoine  (32). 

It  is  recognized  that  the  assumed  analogy  between 
scarlet  fever  and  smallpox  is  a  false  one,  and  that 
scarlet  fever  quite  closely  resembles  diphtheria.  It 
seems  probable  that  the  pathological  process  is  for  the 
most  part  confined  to  the  mucous  surfaces,  chiefly  of 
the  throat  and  nose,  and  that  the  exantham,  and  sub- 
sequent desquamation,  are  due  to  toxins  elaborated  for 
the  most  part  in  the  throat.  The  a  priori  argument  is 
against  the  infectiousness  of  the  exfoliated  skin.  As 
for  direct  evidence  of  such  infectiousness  there  is  none. 
The  burden  of  proof  lies  upon  those  who  assert  the 


THE    INFECTIOUS    PERIOD    IN    SCARLET    FEVER.  29 

affirmative.  On  the  other  hand  there  is  positive  and 
strong  evidenee  that  desquamation  is  not  always  dan- 
gerous. There  is  a  considerable  mass  of  evidence, 
mostly  from  English  hospital  experience,  which  shows 
that  in  the  discharge  of  scarlet  fever  cases,  desquama- 
tion may  be  neglected.  Priestly  (33)  during  a  small 
pox  outbreak  at  Leicester  discharged  120  scarlet 
fever  patients  who  were  desquamating,  and  no  second- 
ary cases  developed  in  any  of  the  homes.  Lauder  at 
Southampton  (34)  sent  out  204  desquamating  patients 
only  2  of  which,  0.98  per  cent,  gave  rise  to  secondary 
cases.  One  of  these  infecting  cases  also  had  nasal  dis- 
charge. Of  the  121  cases  without  desquamation  dis- 
charged during  the  same  period  5,  or  4.13  per  cent 
proved  infective,  all  of  which  had  some  abnormal  dis- 
charge from  nose,  throat,  or  ear.  By  paying  particular 
attention  to  the  mucous  surfaces  while  neglecting  des- 
quamation, Lauder  was  able  to  reduce  the  percentage 
of  return  cases  from  4.27  in  1902  to  2.15  in  1903,  at 
the  same  time  shortening  the  period  of  detention  in 
the  hospital  from  48  to  34  days. 

In  certain  of  the  London  hospitals,  1902-4,  no  case 
was  discharged  while  desquamating,  and  of  6,164  dis- 
charges, 246  or  3.99  per  cent  were  followed  by  return 
cases.  Of  12,000  cases  discharged  from  hospitals  where 
no  attention  was  paid  to  desquamation,  and  many  of 
which  cases  were  desquamating,  return  cases  developed 
269  times,  or  2.24  per  cent.     Undoubtedly  the    hos- 


30  THE  MODE  OF  INFECTION  AND  DUEATION  OF 

pitals  which  paid  little  attention  to  desquamation  paid 
special  attention  to  mucous  discharges  and  hence  the 
lower  number  of  return  cases. 

Urine,  Feces,  Pits  from  Glands.  There  seems  to 
be  no  evidence  either  for  or  against  the  infectiousness 
of  these  excretions. 

Infectivity  with  No  Apparent  Pathological  Condition. 
That  convalescents  from  scarlet  fever  should  carry 
the  virus  of  the  disease  while  exhibiting  no  symptoms 
or  lesions,  is  not  surprising.  It  is  a  phenomenon 
common  to  many  diseases,  and  has  been  particularly 
studied  in  diphtheria  and  typhoid  fever.  The  "  carrier 
case  "  is  coming  to  be  recognized  as  a  most  important, 
if  not  the  most  important,  factor  in  the  spread  of  these 
two  diseases.  As  the  specific  germ  of  scarlet  fever  is 
unknown,  the  evidence  of  the  existence  of  "carriers" 
of  scarlet  fever  is  not  so  conclusive  or  abundant  as  for 
diphtheria  and  typhoid  fever.  Yet  there  is  little  doubt 
that  many  persons  are  infected  with  scarlet  fever  and 
capable  of  giving  the  disease  to  others,  and  yet  pre- 
sent no  symptoms  whatever  of  disease.  Thus  125  of 
the  infecting  cases  discharged  from  the  London  hospi- 
tals and  investigated  by  Cameron  (18)  showed  no  ap- 
parent abnormal  condition.  Millard  (35)  showed  that 
58.2  per  cent  of  the  infecting  cases  at  Birmingham 
were  quite  clear  in  every  way,  and  Boobbyer  states 
that  11  of  26  infecting  cases  at  Nottingham  were  free 


THE    INFECTIOUS    PERIOD    IN    SCARLET    FEVER.  31 

from  symptoms  of  disease.  I  have  kept  no  record  of 
the  condition  of  the  infecting  cases  observed  by  me, 
whether  discharged  from  the  hospital,  or  remaining  in 
their  homes,  but  it  may  be  definitely  stated  that  very 
many  of  these  showed  no  discharge  from  nose  or  ear, 
no  sore  throat,  no  desquamation,  and  in  fact  no  other 
symptoms  of  the  disease.  Cameron  reports  30  in- 
stances, and  Turner  44,  in  which  diphtheria  patients 
carried  scarlet  fever  from  the  hospital  to  their  homes. 
The  presence  of  scarlet  fever  infection  in  these  cases 
had  not  been  indicated  by  any  physical  signs.  There 
is  a  good  deal  of  evidence  that  perfectly  well  persons, 
who  have  never  had  scarlet  fever,  may  nevertheless 
carry  the  poison  in  their  persons  and  transmit  it  to 
others,  but  in  the  absence  of  bacteriological  evidence 
we  have  no  means  of  knowing  how  long  such  infection 
may  last. 

MODES    OF    INFECTION. 

Before  proceeding  to  consider  the  different  modes 
of  infection  in  scarlet  fever  we  may  inquire  what  is 
known  as  to  the  degree  of  contagiousness  of  this  dis- 
ease. I  have  prepared  the  following  table  to  show  it's 
infectivity  in  families  in  which  the  patient  lives  and 
is  kept  at  home  during  the  whole  course  of  the  disease. 


32 


THE  MODE  OF  INFECTION  AND  DURATION  OF 


TABLE  VL    SCARLET  FEVER. 

C  a.ses  from  families  in  which  the  patient  lived  and  remained  at  home  during 

the  whole  illness. 

Age  and  Sex  of  Primary  and  Secondary  Cases. 


Primary  Cases. 


Ages. 


Under  1  yr 
1 


10. 
11. 
12. 
13. 
14. 
15. 
16. 
17. 
18. 
19. 
20. 
A.. 


M. 

is 

< 

F. 

II 

15 

10.9 

6 

4.3 

28 

22.0 

30 

22.6 

61 

35.1 

55 

39.6 

66 

39.1 

83 

45.9 

75 

39.1 

69 

39.4 

74 

38.5 

77 

45.0 

83 

46.8 

91 

45.5 

69 

43.9 

84 

45.2 

62 

40.8 

86 

47.5 

52 

40.0 

75 

43.9 

42 

29.4 

54 

38.6 

32 

25.8 

48 

39.7 

21 

20.4 

36 

33.3 

11 

15.9 

25 

25.3 

24 

26.7 

22 

26.2 

11 

15.7 

15 

19.5 

10 

13.0 

10 

14.9 

7 

10.2 

6 

11.3 

5 

8.8 

8 

13.6 

5 

9.6 

5 

9.8 

3 

6.8 

3 

7.0 

56 

3.1 

63 

3.1 

812 

18.8 

951 

20.7 

Is 


21 

58 

116 

149 

144 

151 

174 

153 

148 

127 

96 

80 

57 

36 

46 

26 

20 

13 

13 

10 

6 

119 


7.6 
22.3 
37.1 
42.6 
39.6 
41.6 
45.7 
44.6 
44.4 
42.2 
33.9 
32.7 
27.0 
21.4 
26.4 
17.7 
13.9 
10 
11 

9 


1,763  19.8 


Secondabt  Oases. 


M. 


16 

32 

40 

41 

37 

30 

22 

28 

12 

18 

8 

13 

6 

2 

3 

2 

5 

2 

2 

0 

13 


4.9 
16.2 
28.3 
38.8 
86.3 
31.4 
30.6 
25.0 
31.1 
15.4 
17.8 

8.7 
15.9 
10.3 

3 

5 


S.O 
8.1 
3.8 
4.8 
.0 
.7 


338      9.6 


7 

24 

17 

21 

37 

31 

32 

30 

30 

24 

18 

16 

16 

5 

10 

9 

6 

2 

q 

2 

2 

34 


376 


5.2 
23.3 
20.2 
21.4 
34.9 
33.0 
29.3 
29.4 
31.6 
25.0 
20.9 
21.9 
22.2 

6.8 
16.] 
14.5 
10.5 

4.3 

5. 

4.2 

5.0 

1.7 


10.3 


13 

40 

49 

61 

78 

68 

62 

52 

58 

36 

36 

24 

29 

11 

12 

12 

8 

7 

5 

4 

2 

47 


714 


<! 


5.1 

19.8 

24.9 

30.3 

35.6 

32.1 

30.0 

27.4 

31.4 

20.7 

19.3 

14.5 

18.8 

8.3 

9.4 

9.9 

6.5 

6.4 

4.8 

4.2 

2.5 

1.3 


10.0 


THE    INFECTIOUS    PERIOD   IN    SCARLET    FEVEU,  33 

While  it  is  most  important  to  know  to  what  degree 
scarlet  fever  may  be  expected  to  spread  through  the 
family,  it  is  of  more  importance  from  an  epidemiologi- 
cal point  of  view  to  know  what  the  chance  is  of  its 
spreading  from  family  to  family,  and  in  schools  and 
similar  places.  Instances  are  not  rare  where  children 
presumably  in  the  infectious  stage  of  scarlet  fever, 
have  mingled  freely  with  others  for  many  days,  or 
perhaps  weeks,  with  little  or  no  extension  of  the  dis- 
ease. I  have  notes  of  an  instance  where  a  boy  with 
scarlet  fever  in  the  sore  throat  stage,  attended  a  Sun- 
day School  festival,  and  no  other  case  developed 
among  the  large  number  of  children  present.  At  an 
infant  asylum  a  child  was  sick  with  mild  scarlet  fever 
for  17  days,  mingling  freely  with  about  75  children, 
mostly  under  5  years  of  age,  and  only  3  other  cases 
resulted.  At  a  large  school,  a  girl  returned  at  the  end 
of  the  first  week  of  an  attack  of  scarlet  fever,  and  con- 
tinned  her  attendance  for  20  days.  Only  3  or  4  cases 
developed  in  that  school.  Similar  and  even  more 
marked  instances  of  apparently  feeble  infectivity  are 
reported  by  others,  and  the  same  phenomenon  has 
been  noted  in  smallpox  and  diphtheria.  In  the  latter 
disease  bacteriology  has  shown  us  that  it  is  quite  com- 
mon for  "carriers"  to  mingle  freely  with  others  with- 
out spreading  the  disease.  I  have  known  of  a  teacher 
with  virulent  diphtheria  bacilli  in  her   throat  from  the 


34  THE  MODE  OF  INFECTION  AND  DURATION  OF 

first  of  January  to  the  middle  of  April,  who  taught  in 
a  kindergarten  all  that  time,  but  who  did  not  transmit 
the  disease  to  any  one.  Hence  we  should  not  be  sur- 
prised to  find  that  scarlet  fever,  except  under  condi- 
tions of  the  closest  contact,  does  not  show  a  very  high 
degree  of  contagiousness. 

In  Providence  most  people  live  in  tenement  houses 
with  one  or  more  other  families,  and  the  amount  of 
infection  of  second  families  in  the  house,  and  the  con- 
ditions under  which  this  takes  place  is  of  much  epi- 
demiological interest.  I  have  records  of  such  an  ex- 
tension of  the  disease  for  a  number  of  years.  Of  4033 
other  families  living  in  the  same  house  with  the  family 
first  attacked,  and  using  the  same  doors  and  passage- 
ways, 291  or  7.2  per  cent  have  been  invaded.  This  is 
a  surprisingly  small  percentage,  when  it  is  remembered 
that  most  of  the  families  are  poor,  or  at  least  in 
moderate  circumstances,  and  that  the  houses  are  fre- 
quently very  much  crowded,  and  the  people  often 
ignorant. and  careless.  Observation  has  shown  that  a 
large  part  of  the  infection  takes  place  before  the  dis- 
ease is  recognized,  and  while  there  is  a  free  mingling 
of  the  children  and  perhaps  other  members  of  the 
families,  and  a  certain  other  part  of  the  cases  are  due 
to  a  mingling  after  the  termination  of  isolation,  when 
it  is  supposed  that  the  infective  stage  is  passed.  But 
as  we  have  seen  the  infective  stage  in  a  small  percen- 
tage of  cases  continues   unrecognized,  and   often  un- 


THE   INFECTIOUS    PBKIOD    IN    SCARLET    FEVEK.  35 

recognizable  for  a  long  time.  The  time  at  which  in- 
fection of  second  families  takes  place  is  shown  by  the 
table  on  page  13  which,  however,  only  covers  the 
five  years  during  which  these  special  data  have  been 
tabulated.  Of  80  families  which  developed  the  disease 
while  the  warning  sign  was  on  the  house  54  were  dur- 
ing the  first  two  weeks  of  the  initial  sickness.  Most  of 
these  cases  probably  contracted  the  disease  before  the 
house  was  placarded.  From  the  end  of  the  second 
week  of  the  disease  in  the  first  family  to  the  end  of 
the  second  month,  there  were  only  24  instances  in 
which  there  was  extension  of  the  disease  from  one 
family  to  another  in  the  same  house.  This  is  only 
1.3  per  cent  of  the  1,888  families  exposed. 

It  appears  then  that  scarlet  fever  almost  never  ex- 
tends from  one  family  to  another  in  the  same  house, 
except  when  there  is  free  communication  between  the 
members,  usually  before  the  disease  is  recognized, 
more  rarely  after  the  termination  of  isolation,  and 
more  rarely  still  while  the  warning  sign  is  upon  the 
house.  This  happens  in  houses  where  two,  and  per- 
haps four  or  six  families,  use  the  same  hallways,  doors, 
cellars  and  perhaps  the  same  water  closets.  The 
woodwork  in  these  houses  is  rarely  cleaned,  and  the 
children  and  grown  people  in  the  infected  family,  even 
the  mother  who  nurses  the  patient,  are  constantly  run- 
ning their  hands  up  and  down  the  stair-rail,  along  the 
walls,  and  are  opening   and    closing   the    doors.     The 


36  THE  MODE  OF  INFECTION  AND  DURATION  OF 

mother  will  carry  slops  to  the  cellar,  and  the  garbage 
and  refuse  to  the  yard.  That  the  disease  does  not 
spread  under  these  conditions  throws  light  on  the 
degree  of  infectivity  and  the  mode  of  infection  in  this 
disease. 

Among  the  modes  of  infection  worthy  of  considera- 
tion are  the  following : 

Infectio7i  hy  Contact.  This  is  the  most  obvious 
means  by  which  the  extension  of  the  disease  may  take 
place.  The  term  is  coming  into  quite  general  use  but 
is  not  accurately  defined.  In  this  connection  it  means 
the  quite  direct  transference,  of  quite  fresh  infective 
material.  The  transference  may  be  immediate,  as  in 
kissing,  or  far  more  often,  mediate,  as  by  two  persons 
drinking  from  the  same  glass,  or  moistening  the  same 
pencil  in  the  mouth.  There  are  a  thousand  and  one 
ways  in  which  young  children  thus  transfer  the  secre- 
tions of  the  mouth  and  nose  from  one  to  another. 
They  are  constantly  putting  their  fingers  and  every 
imaginable  article,  into  the  mouth,  or  are  boring  the  nose 
with  the  fingers.  Toys,  cups,  spoons,  pencils,  candy, 
food,  string  and  countless  other  things,  may  thus  easily 
become  the  bearers  of  the  secretions  from  child  to  child, 
and  there  is  often  likely  to  be  an  even  more  direct 
transfer  as  they  romp  and  tumble  over  each  other  in 
play.  The  opportunities  for  such  contact  infection  in 
the  family  are  so  numerous  and  constant  that  the  won- 


THE    INFECTIOUS    PERIOD   IN    SCARLET    FEVER.  37 

der  is  not  that  infection  takes  place,  but  that  half  of 
the  children  of  even  the  most  susceptible  age  escape 
during  the  month  or  six  weeks'  presence  of  scarlet 
fever.  It  is  not  improbable  that  apparent  differences 
in  age  and  sex  "susceptibility"  to  the  disease,  may  be 
largely  an  expression  of  the  chance  for  contact  with 
the  patient.  Infants  are  less  susceptible  perhaps  be- 
cause they  do  not  mingle  freely  with  and  play  with 
other  children.  The  years  of  greatest  susceptibility, 
from  two  to  ten  are  exactly  those  years  in  which  chil- 
dren are  careless  and  have  little  idea  of  cleanliness, 
and  are  constantly  coming  into  the  closest  possible 
contact  with  one  another.  A  noticeable  feature  of 
family  infection  is  that  women  over  16  years  of  age 
are  more  than  twice  as  likely  to  contract  scarlet  fever 
when  it  has  once  invaded  the  family,  than  are  men  of 
the  same  ages,  a  fact  to  be  explained  perhaps  by  the 
women  coming  into  far  more  intimate  personal  contact 
with  the  patient  than  do  the  men.  The  constant 
escape  from  the  disease  of  the  vast  majority  of  other 
families  in  the  same  house,  speaks  for  the  necessity  of 
quite  close  contact  to  insure  infection.  This  view  that 
contact  infection  is  the  chief  mode  of  transference  of 
scarlet  fever  is  coming  to  be  recognized  by  many  of 
the  most  careful  observers,  especially  in  England  and 
France.  Thus  Cameron  (12)  gives  several  instances  in 
which  the  development  of  return  cases  did  not  take 
place  as  long  as  the  infecting  case  did  not  come  into 


38  THE  MODE  OF  INFECTION  AND  DURATION  OF 

immediate  contact  with  susceptible  members  of  the 
family.  Niven  in  Manchester  fi'om  a  study  of  return 
cases  in  that  city  is  convinced  that  if  the  children  can  be 
kept  slightly  apart  in  the  family,  there  is  no  transfer- 
ence of  the  disease.  That  there  is  much  good  evidence 
that  scarlet  fever  does  not  spread  in  the  absence  of 
contact  will  be  shown  when  considering  the  possibility 
of  infection  by  air. 

Doubtless  the  chief  reason  for  scepticism  as  to  the 
sufficiency  of  contact  infection  to  account  for  the  ex- 
tension of  scarlet  fever,  is  the  fact  that  in  a  large  pro- 
portion of  cases  it  is  impossible  to  find  any  connection 
with  a  previous  case.  If  there  is  no  change  for  contact 
infection  from  another  case,  it  seems  to  be  necessary 
to  discover  some  other  and  more  circuitous,  or  less  vis- 
ible, mode  of  transference.  This  point  of  view  depends 
upon  the  assumption  that  all  or  nearly  all  persons 
infected  with  scarlet  fever  are  recognized  as  such. 
This  assumption  at  the  present  day  is  entirely  unwar- 
ranted. It  is  now  well  known  that  in  many  of  the  in- 
fectious diseases,  atypical  forms,  not  easily  recognized 
clinically  and  frequently  not  seen  by  a  physician,  are 
very  numerous,  perhaps  more  numerous  than  are  the 
cases  seen  and  recognized  by  medical  men.  This  is 
noticeably  true  of  diphtheria,  typhoid  fever  and  yellow 
fever.  It  has  also,  within  a  few  years,  been  learned, 
what  was  never  before  suspected,  that  in  many  diseases 
an  even  larger  number  of  persons  are  the  "  carriers  " 


THE    INFECTIOUS    PERIOD    IN    SCARLET    FEVER.  39 

of  disease  germs  without  exhibiting  any  symptoms  of 
disease.  This  has  been  proved  true  of  diphtheria, 
typhoid  fever,  malaria  and  particularly  of  cerebro-spi- 
nal-meningitis. 

Unfortunately  the  laboratory  cannot  as  yet  help  us 
in  findino:  the  "  missed  cases  "  and  '•  carriers  "  of  scarlet 
fever.  But  all  who  have  made  a  careful  study  of  this 
disease  know  that  there  are  very  frequently  seen  cases 
with  a  scarcely  discernible  indefinite  rash,  lasting  for 
only  a  few  hours,  a  rise  in  temperature  of  only  a  degree 
or  two,  lasting  also  only  a  few  hours,  and  the  merest 
trace  of  sore  throat.  Sometimes  the  rash  may  be 
entirely  absent.  In  institutions  and  families,  such 
cases,  considered  doubtful  at  first,  or  perhaps  neglected, 
prove  to  be  the  origin  of  typical  symptoms  in  others. 
They  are  the  missed  cases  which  are  such  a  factor  in 
the  maintenance  of  this  disease.  There  are  many 
references  to  them  in  the  reports  of  health  officers  and 
in  medical  literature.  Among  others  who  report  such 
atypical  cases  are  Newsholme  (11),  Gaziot  (36),  Welch 
and  Shamberg  (37),  and  Cameron  (38).  In  most  of  these 
"missed"  cases  there  were  some  slight  symptoms,  but 
overlooked  or  misunderstood  at  the  time.  In  Manchester 
in  1906  there  were  discovered  229  missed  cases,  mostly 
of  a  mild  character.  From  these  139  other  cases  had 
developed  (39).  True  "  carriers,"  that  is  perfectly 
well  persons,  are  sometimes  reported.  Thus  I  saw  an 
instance  where  a  woman  apparently  so  carried  scarlet 


40  THE  MODE  OF  INFECTION  AND  DURATION  OF 

fever  to  her  child.  She  had  been  taking  care  of 
another  child,  and  after  an  entire  change  of  clothing, 
bath  and  shampoo,  visited  the  first  named  child  who 
was  taken  sick  two  days  later.  Newsholme  reports 
what  he  thinks  are  possibly,  or  even  probably,  similar 
cases.  Newman  (40),  of  Finsbury,  (London)  noted 
five  carriers  among  school  children,  three  of  whom, 
though  they  had  never  had  the  disease,  transmitted  it 
to  others.  Cameron  (41)  reports  many  such  cases. 
While  the  proof  of  the  number  of  carriers  and  missed 
cases  is  not  so  conclusive  as  it  is  for  diphtheria  and 
typhoid  fever,  and  never  can  be  in  the  absence  of  lab- 
oratory evidence,  it  is  yet  sufficient  to  warrant  the 
belief  that  the  unrecognized  sources  of  infection  are 
numerous  enough  to  permit  the  origin  from  them  by 
contact  infection  of  all  the  recognized  cases  of  the 
disease. 

Infection  by  Fomites.  Whenever  in  the  past  it  was 
impossible  to  trace  any  direct  connection  between  cases 
of  scarlet  fever,  indirect  means  of  communication  were 
sought  for,  and  it  was  not  infrequently  found  that  a 
toy,  book,  clothing,  or  some  other  material  thing, 
which  had  previously  been  used  by  one  scarlet  fever 
patient,  was  used  by  another  case  a  short  time  before 
the  development  of  the  disease.  These  supposed 
bearers  of  infection  are  called  fomites,  and  it  has  been 
alleged  that  they  can  retain  their  virulence  for  many 


THE   INFECTIOUS    PERIOD   IN    SCAELET    FEVER.  41 

weeks,  months  and  even  years.  It  is  seen  that  the 
distinction  between  immediate  contact  and  fomites  in- 
fection is  not  a  sharp  one.  The  common  usage  is  to 
apply  the  term  contact  infection  when  the  interval  in 
time  is  short,  perhaps  a  few  hours,  often  only  a  few 
minutes,  and  to  use  the  word  fomites  when  the  interval 
is  long.  In  contact  infection  the  infective  material  is 
moist,  or  at  least  not  dry,  in  the  case  of  fomites,  we 
commonly  think  of  the  infective  material  as  pretty 
well  dried. 

It  is  unnecessary  to  give  instances  of  alleged  fomites 
infection  in  this  disease.  They  are  found  scattered 
through  medical  literature  in  almost  every  article  and 
text  book  dealing  with  scarlet  fever.  In  many  of 
them  the  disease  is  traced  to  an  infected  schoolroom 
or  house,  or  to  clothing,  books  or  toys  which  have  been 
carried  long  distances.  Often  no  mention  is  made  of 
the  occupants  of  the  room,  or  the  bearers  of  the  goods, 
who  are  much  more  likely  to  have  been  the  "  carriers  " 
of  living  germs,  than  the  things  were  to  bear  even 
dead  germs,  a  fact  which  is  rarely  recognized  by  the 
narrators.  Often  no  pretence  is  made  to  exclude 
other  sources  of  infection,  and  in  most  instances  there 
is  merely  a  possibility  and  not  even  a  probability,  that 
the  fomites  were  really  the  source  of  the  disease.  The 
utter  destruction  by  Reed,  of  the  implicit  confidence 
formerly  placed  in  the  role  played  by  fomites  in  the 
spread  of  yellow  fever,  should  make  us  wary  of  admit- 


42  THE  MODE  OF  INFECTION  AND  DURATION  OF 

ting  the  much  less  convincing  proofs  of  fomites  infec- 
tion in  scarlet  fever.  Diphtheria  also  has  long  been 
considered  a  fomites  borne  disease,  but  the  entire 
abandonment  of  disinfection  after  that  disease,  in 
Providence  (42)  has  not  resulted  in  any  increase  in  the 
number  of  cases.  There  is  certainly  no  stronger  evi- 
dence of  infection  by  fomites  in  scarlet  fever  than 
there  was  for  diphtheria.  Lemoine  (43)  has  shown  that 
in  the  military  hospital  at  Yal  de  Grace  it  was  possible 
to  put  a  considerable  number  of  persons  in  a  ward  just 
cleared  of  scarlet  fever  patients  and  with  no  disinfec- 
tion, and  yet  without  any  one  contracting  the  disease. 
At  a  recent  conference  (43)  in  Paris,  Courmont,  Comby 
and  others  affirmed  that  the  very  thorough  disinfection 
of  goods  and  houses  carried  on  by  the  sanitary  authori- 
ties of  that  city  is  unnecessary,  and  has  no  effect  in 
diminishing  the  spread  of  scarlet  fever,  diphtheria  or 
measles.  In  England  it  has  been  claimed  by  some  that 
the  alleged  "  return  cases  "  of  scarlet  fever  are  not  so 
often  due  to  the  return  of  the  patient,  as  to  failure  of 
disinfection,  but  Cameron  (44)  has  shown  that  this 
cannot  be  true,  for  the  cases  are  associated  chiefly  with 
patients  of  certain  ages,  and  particularly  with  those 
suffering  from  complications. 

Perhaps  the  best  evidence  that  infection  by  fomites 
is  not  easy,  is  found  in  the  fact  previously  referred  to, 
that  there  is  so  little  extension  of  the  disease  in  tene- 
ment houses.     If  the  mothers,  fathers,  brothers  and 


THE    INFECTIOUS    PERIOD    IN    SCARLET    FEVER.  43 

sisters,  of  the  patient,  do  not  infect  the  hallways,  stair 
rails,  doors  and  water  closets  so  as  to  cause  the  disease 
in  the  other  inmates  of  the  house,  can  there  be  any 
appreciable  danger  of  their  carrying  the  virus  in  their 
clothes  to  their  work  or  play  ? 

It  will  not  be  denied  that  infection  by  fomites  may 
not  take  place  in  scarlet  fever,  nor  that  there  may  be 
some  instances  of  long  persisting  inf ectivity  by  fomites. 
But  it  is  affirmed  that  there  is  no  evidence  that 
such  a  mode  of  infection  plays  any  appreciable  part  in 
the  extension  of  the  disease,  and  there  is  much  e^ddence 
that  it  does  not. 

Lifection  hy  Air.  Another  explanation  of  the 
source  of  scarlet  fever  which  cannot  be  traced  to 
direct  contact  with  another  case,  is  that  the  infection 
is  airborne.  This  idea  of  the  importance  of  airborne 
infection  depends  very  largely  on  the  belief  that  the 
desquamating  epidermis  is  infectious,  a  belief  for 
which  it  has  been  shown  there  is  no  evidence.  The 
writer  like  every  health  officer,  has  frequently  noted 
that  a  case  of  this  disease  may  remain  in  school  or 
hospital  ward  for  days,  or  sometimes  for  weeks,  with- 
out another  case  developing,  or  at  most  only  one  or 
two  cases.  Such  facts  indicate  that  the  disease  is  not 
easily  airborne.  Visitors  to  fever  hospitals  do  not 
contract  scarlet  fever.  Thus  of  300  to  400  non- 
immune students  who  ATsited  the  scarlet  fever  wards  of 


44  THE  MODE  OF  INFECTION  AND  DURATION  OF 

the  Philadelphia  hospital,  remaining  in  the  ward  from 
twenty  minutes  to  an  hour,  not  one  contracted  the 
disease  (46).  Oftentimes  scarlet  fever  does  attack 
other  patients  in  hospitals  but  it  is  in  a  manner  to  in- 
dicate contact  rather  than  airborne  infection.  When 
contact  infection  is  rigidly  guarded  against  as  in  the 
Pasteur  Hospital  in  Paris,  scarlet  fever  may  be  and  is 
treated  in  the  same  ward  with  other  diseases  without 
cross  infection. 

Attention  has  already  been  called  to  the  compara- 
tive rarity  with  which  scarlet  fever  passes  from  one 
family  to  another  in  the  same  house,  and  I  have 
shown  that  when  it  does  so  occur  it  is  almost  always 
due  to  free  communication  between  the  families,  that 
is  to  contact  infection.  Notwithstanding  the  fact  that 
the  doors  of  tenements  are  frequently  opposite  one 
another  and  that  during  a  considerable  part  of  the 
year  the  doors  and  windows  are  wide  open,  infection 
by  the  air  does  not  take  place. 

If  scarlet  fever  is  not  airborne  from  family  to  family 
in  the  house,  one  would  not  expect  it  to  be  borne 
from  house  to  house  by  the  air.  Yet  such  a  claim  is 
sometimes  made,  that  the  virus  of  the  disease  may  thus 
be  transmitted  a  considerable  distance.  A  number  of 
the  reports  of  the  health  department  of  Philadelphia 
contain  shaded  maps  to  show  the  greater  prevalence 
of  this  disease,  as  well  as  of  smallpox,  in  those  parts 
of   the    city  near  the  hospital.     I  do  not  think  that 


THE    INFECTIOUS    PERIOD    IN    SCARLET    FEVER.  45 

much  value  attaches  to  such  maps  for  there  are  too 
many  factors  involved,  and  very  rarely  is  the  intensity 
of  the  disease  as  great  close  to  the  hospital  as  the 
theory  demands.  Moreover  around  very  many  hospi- 
tals no  such  distribution  of  the  disease  can  be  shown. 
Thus  Tarnissier  (46)  in  Paris  found  that  Enfantes 
Malades  and  Trousseau  hospitals  could  not  be  con- 
sidered foci  of  infection.  The  same  is  true  of  the 
scarlet  fever  wards  in  Providence,  in  Detroit,  and  in 
Boston.  In  the  latter  city  (47)  for  the  period  studied 
there  Avere  no  cases  of  the  disease  within  one  eighth 
of  a  mile  of  the  hospital,  while  in  the  next  eighth  of  a 
mile  circle  there  were  68  cases,  in  the  next  71,  in  the 
next  75,  and  in  the  next  72. 

Where  various  contagious  diseases  are  treated  in 
different  wards  of  the  same  hospital  there  is  sometimes 
cross  infection.  But  this  occurs  so  irregularly  as  to 
time  and  place,  and  is  so  limited  in  amount  that  it  can 
scarcely  be  attributed  to  anything  but  contact  infec- 
tion. As  most  of  the  physicians  and  nurses  in  our  con- 
tagious hospitals  have  no  appreciation  of  what  true 
medical  asepsis  really  means,  it  is  surprising  that  we 
see  as  little  cross  infection  as  we  do. 

Perhaps  the  best  evidence  we  have  that  scarlet  fever 
is  not  airborne  is  that  furnished  by  the  Pasteur  Hospi- 
tal in  Paris.  In  this  hospital,  patients  with  different 
diseases  are  cared  for  in  separate  rooms  opening  out 
of  a  common  corridor.     If  air  infection  is  dangerous 


46  THE  MODE  OF  INFECTION  AND  DUKATION  OF 

anywhere  it  ought  to  be  under  these  conditions.  Be- 
tween October  1,  1900,  when  the  hospital  was  opened, 
and  April  19,  1903,  2,000  patients  were  received,  of 
whom  92  had  scarlet  fever,  but  in  no  instance  did  any 
one  in  the  hospital  contract  this  disease  (48). 

There  is  no  direct  bacteriological  evidence  bearing 
on  the  question  of  the  aerial  convection  of  the  scarlet 
fever  virus.  Yet  bacteriology  does  offer  some  sugges- 
tions. As  the  skin  is  probably  not  infectious,  we  must 
look  to  the  mucous  surfaces  for  the  source  of  our  air- 
borne infection,  but  the  laboratory  has  shown  us  that 
bacteria  and  other  solid  particles  are  not  thrown  off 
from  moist  surfaces,  but  are  rather  entangled  in  them. 
The  only  way  that  infection  can  pass  from  throat  or 
nose,  is  by  means  of  the  little  droplets  wlach  are 
thrown  off  in  coughing,  sneezing,  and  even  m  talking. 
It  has  been  shown  that  usually  the  droplets  which  are 
large  enough  to  infect,  speedily  sink,  so  that  droplet 
infection  will  rarely  take  place  over  a  yard  from  the 
patient.  Droplet  infection  at  short  distances  is  doubt- 
less possible  in  scarlet  fever,  and  in  this  sense  it  is  an 
airborne  disease.  But  for  all  practical  purposes  droplet 
infection  more  nearly  resembles  contact  infection  than 
it  does  aerial  infection  as  the  latter  is  generally  under- 
stood. 

Infection  hy  Milk,  It  has  long  been  known  that 
milk  may  be  the  means  of  spreading  the  virus  of  scar- 


THE    INFECTIOUS    PERIOD    IN    SCARLET    FEVER.  47 

let  fever,  and  a  considerable  number  of  outbreaks  of 
the  disease  have  been  traced  to  this  source.  A  federal 
report  issued  in  1908  (49),  notes  51.  such  outbreaks, 
but  doubtless  others  have  been  reported  which  were 
not  included  in  this  enumeration.  This  seems  like  a 
serious  indictment  of  milk,  but  when  it  is  taken  in  con- 
nection with  the. vast  number  of  cases  of  scarlet  fever 
that  have  occurred  in  Europe  and  America  during  the 
last  thirty  or  forty  years,  it  will  appear  that  milk 
infection  is  not  after  all  a  very  important  factor  in  the 
spread  of  this  disease.  Milk  outbreaks  of  scarlet  fever, 
like  milk  outbreaks  of  other  diseases,  are  characterized 
by  a  sudden  onset,  and  the  occurrence  of  a  large  num- 
ber of  cases  within  a  brief  period.  As  the  incubation 
of  scarlet  fever  is  short,  and  the  infection  of  the  milk 
is  usually  temporary,  the  cases  are  often  massed  in  a 
period  of  a  few  days  only.  Thus  of  the  717  cases  in 
the  milk  outbreak  in  Boston  in  1907  (50),  485  occurred 
within  6  days.  The  exceptionally  explosive  character 
of  these  outbreaks  renders  it  likely  that  few  escape 
notice,  yet  it  appears  that  they  are  quite  rarely  re- 
ported. Only  one  has  come  to  the  notice  of  the  writer 
during  an  experience  of  many  years.  In  this  outbreak 
there  were  26  cases,  a  very  small  part  of  the  13,001 
cases  which  have  come  under  his  observation. 

It  matters  little  for  our  present  purpose,  how  the 
milk  becomes  infected.  It  has  been  claimed  by  some 
that  cows  may  have  scarlet  fever  and  infect  the  milk 


48  THE  MODE  OF  INFECTION  AND  DTJEATION  OF 

directly.  Klein  at  one  time  strongly  urged  this  source, 
and  thought  that  he  had  found  in  the  cows  the  strep- 
tococcus or  diplococcus  which  he  believed  was  the 
cause  of  the  disease.  But  his  observations  have  not 
been  verified,  and  it  is  generally  believed  at  the  pre- 
sent time  that  milk  receives  scarlet  fever  infection 
from  human  sources  exclusively. 

While  it  is  certain  that  occasionally  extensive  and 
spectacular  outbreaks  of  scarlet  fever  are  caused  by 
infected  milk,  and  that  every  effort  should  be  made  to 
prevent  such  milk  infection,  it  is  equally  certain  that 
milk  infection  plays  but  an  infinitesimal  part  in  the 
epidemiology  of  scarlet  fever. 

SUMMARY. 

1.  The  micro-organism  which  presumably  is  the 
cause  of  scarlet  fever  is  unknown. 

2.  Evidence  points  to  scarlet  fever  as  a  local  dis- 
ease of  the  throat  and  nose,  as  is  diphtheria. 

3.  The  rash  and  desquamation  are  more  likely  to 
be  due  to  the  action  of  a  toxin  than  to  the  presence  of 
the  pathogenic  organism  in  the  skin. 

4.  The  incubation,  or  more  properly  latent  period, 
of  scarlet  fever  is  usually  short,  but  may  be  prolonged 

for  weeks. 


THE    INFECTIOUS    PERIOD    IN    SCARLET    FEVER.  49 

5.  Scarlet  fever  is  infectious  with  the  appearance 
of  the  first  symptoms.  The  height  of  the  infectivity 
is  coincident  with  activity  of  the  throat  symptoms.  It 
then  rapidly  declines.  In  a  small  proportion  of  cases 
it  may  persist  for  months. 

6.  Prolonged  infectivity  is  often  associated  with 
the  persistence  of  the  pathologic  process  in  throat, 
nose  and  ear. 

7.  The  secretions  of  the  throat  and  nose  are 
probably  the  chief  source  of  infection. 

8.  The  exfoliated  epidermis  is  probably  not  infec- 
tious. 

9.  The  infectivity  of  the  disease  is  less  than  is 
generally  believed. 

10.  In  the  great  majority  of  cases  scarlet  fever  ex- 
tends by  contact  infection. 

11.  Infection  by  fomites  is  of  little  importance. 

12.  Except  by  droplet  infection,  which  has  a  very 
limited  range,  scarlet  fever  is  probably  almost  never 
an  airborne  disease. 

13.  Milk  infection  though  a  real  danger,  is  the 
source  of  comparatively  few  cases. 


50  THE  MODE  OF  INFECTION  AND  DURATION  OF 


REFERENCES. 


(1)  Mallory,  Jour.  Med.  Research,  Jan.,  1904. 

(2)  Gamaleia,  Berl.  klin.  Woch.  1908,  XLV,  s.  1T95. 

(3)  Boston  Med.  and  Surg.  Jour.  May  22,  and  29,  1902,  pp.  533  and  561. 

(4)  Murchison,  Clin.   Soc.  Trans.,  1878,  XI,  238. 

(5)  Acute  Contagious  Diseases  p.  264. 

(o)  Barlow,  Practitioner,  Lond.,  Dec,    1907. 

(7)  Zilgien  Med.  infantile,  Par.,  1908,  V.,  p.  105. 

(8)  Turner,  Report  on  Return  Cases  of  Scarlet  Fever  and  Diphtheria 
in  London,  1902-4,  p.  3. 

(9)  Cameron,  Rep.  on  Return  Cases  of  Scarlet  Fever  and  Diphtheria 
in  London,  1901-2,  p.  4. 

(10)  Turner' s  Report  on  Return  Cases  of  Scarlet  Fever  and  Diphtheria 
in  London,  1902-4,  p.  18. 

(11)  ISTewsholme,  Med.  Chirurg.  Trans.,  Vol.  87. 

(12)  Cameron  Rep.  on  Return  Cases  of  Scarlet  Fever  and  Diphtheria 
in  London,  1901-2,  p.  98. 

(13)  Simpson,  Report  on  Return  Cases  of  Scarlet  Fever  and  Diph- 
theria in  London,  1898-9,  p.  16. 

(14)  Cameron,  Report  on  Return  Cases  of   Scarlet  Fever  and  Diph- 
theria in  London,  1902-4,  p.  27. 

(15)  Jurgensen,  Scarlet  Fever,  Nothnagel's  Encyclopedia,  p.  420. 

(16)  Stickler,  N.  Y.,  Med.  Rec,  1899,  II,  p.  363. 

(17)  Grunbaum,  Br.  Med.  Jour.  1904,  I,  p.  816. 

(18)  Cameron,  Report  on  Return  Cases  Scarlet  Fever  and  Diphtheria 
Lend.,  1901-2,  p.  13. 


THE   INFECTIOUS   PERIOD   IN   SCARLET   FEVER.  51 

(19)     Cameron,  Report  on  Return  Cases  Scarlet  fever  and  Diphtheria, 
Lond.,  1901-2,  pp.  38  and  79. 


(20 

(21 
Lond 

(22 

(23 

(24 

(25 

(26 

(27: 

(28 
Lond 

(29 

(30 

(31 
Lond 

(32 

(33 

(34 

(35 

(36 
1903. 

(37 

(88 


Newaholme,  Jour.  Hyg.,  1902,  II,  p.  150. 

Cameron,  Report  on  Return  Cases  Scarlet  Fever  and  Diphtheria, 
,    1901-2,  p.  90. 

Ibid.,  p.  18. 

Boobbyer,  Brit.  Med.  Jour.,  Aug.  31,  1895,  p.  523. 

Richards,  Ibid,  p.  524. 

Gilbert,  Brit.  Med.  Jour.,  Sept.  14,  1895. 

Millard,  Lancet,  Apr.  5,  1902,  p.  959. 

Lauder,  Lancet,  Mar.  12,  1904,  p.  712. 

Cameron,  Report  on  Return  Cases  Scarlet  Fever  and  Diphtheria, 
,  1901-2,  p.  19. 

Bond,  Public  Health,  XV,  p.  244. 

Moore,  Public  Health,  XXI,  p.  148. 

Turner,  Report  on  Return  Cases  Scarlet  Fever  and  Diphtheria, 
,  1902-4,  p.  6. 

Lemoine,  Bull,  de  la  soc.  med.  milit.  fran9ois0,  1907,  p.  399. 

Priestly,  Trans.  Epidem.Soc,  1894-5,  XIV. 

Lauder,  Lancet  1904,  i.,  p.  712. 

Millard,  Br.  Med.  Jour.,  Sept.  3,  1898. 

Gaziot.  Soc.  med.  des  hop.,  July  3,  1903.    Sem.  med.,  June  24, 
Caducee,  Par.  1903,  III,  p.  273. 

The  Acute  Infectious  Diseases,  p.  390. 

Cameron,  Report  on  Return  Oases  Scarlet  Fever  and  Diphtheria 


in  London,  1901-2,  p.  78. 

(39)     Report  on  the  Health  of  the  City  of  Manchester,  1906,  p.  43. 


52  INFECTIOUS   PEBIOD   IN    SCAKLBT    FEVER. 

(40)  London,  Kep.  of  Med.  Of.  of  Health  to  Co.  Council,  1904,  p.  27, 

(41)  Cameron,  Report  on  Return  Cases  Scarlet  Fever  and  Diphtheria, 
London.  1901-2,  p.  128. 

(42)  Jour.  Am.  Med.  Asso.,  1906,  XVII,  p.  574. 

(43)  Rev.  de  hyg.,  Paris,  1907,  XXIX,  p.  1057  and  Bull,  et  mem.  see. 
med.  des.  hop.,  1909,  XXVI,  p.  588. 

(44)  Cameron,  Report  on  Return  Cases  of  Scarlet  Fever  and  Diph- 
theria, London,  1901-2,  p.  37. 

(46)     The  Acute  Infectious  Diseases,  p.  346. 

(46)  Tarnissier  La  sem.  med,,  1903,  p.  267. 

(47)  Med.  and  Surg.  Rep.  of  Boston  City  Hospital,  1897. 

(48)  Rev.  d'hyg.  20  Mass.  1903,  p.  256.     Bull.  med.   19  Mass.,  1904, 
p.  251. 

(49)  Hyg.  Lab.  Bull.  No.  41,  U.  S.  P.  H.  &  M.  H.  S. 

(50)  Ibid,  p.  94. 


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